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Lei H, Preitner F, Labouèbe G, Gruetter R, Thorens B. Glucose transporter 2 mediates the hypoglycemia-induced increase in cerebral blood flow. J Cereb Blood Flow Metab 2019; 39:1725-1736. [PMID: 29561214 PMCID: PMC6727137 DOI: 10.1177/0271678x18766743] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Glucose transporter 2 (Glut2)-positive cells are sparsely distributed in brain and play an important role in the stimulation of glucagon secretion in response to hypoglycemia. We aimed to determine if Glut2-positive cells can influence another response to hypoglycemia, i.e. increased cerebral blood flow (CBF). CBF of adult male mice devoid of Glut2, either globally (ripglut1:glut2-/-) or in the nervous system only (NG2KO), and their respective controls were studied under basal glycemia and insulin-induced hypoglycemia using quantitative perfusion magnetic resonance imaging at 9.4 T. The effect on CBF of optogenetic activation of hypoglycemia responsive Glut2-positive neurons of the paraventricular thalamic area was measured in mice expressing channelrhodopsin2 under the control of the Glut2 promoter. We found that in both ripglut1:glut2-/- mice and NG2KO mice, CBF in basal conditions was higher than in their respective controls and not further activated by hypoglycemia, as measured in the hippocampus, hypothalamus and whole brain. Conversely, optogenetic activation of Glut2-positive cells in the paraventricular thalamic nucleus induced a local increase in CBF similar to that induced by hypoglycemia. Thus, Glut2 expression in the nervous system is required for the control of CBF in response to changes in blood glucose concentrations.
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Affiliation(s)
- Hongxia Lei
- 1 AIT, Center for Biomedical Imaging (CIBM-AIT), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,2 Department of Radiology, University of Geneva, Geneva, Switzerland
| | - Frédéric Preitner
- 3 Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland.,4 Mouse Metabolic Evaluation Facility, Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Gwenaël Labouèbe
- 3 Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Rolf Gruetter
- 1 AIT, Center for Biomedical Imaging (CIBM-AIT), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,2 Department of Radiology, University of Geneva, Geneva, Switzerland.,5 Department of Radiology, University of Lausanne, Lausanne, Switzerland
| | - Bernard Thorens
- 3 Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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Falkowska A, Gutowska I, Goschorska M, Nowacki P, Chlubek D, Baranowska-Bosiacka I. Energy Metabolism of the Brain, Including the Cooperation between Astrocytes and Neurons, Especially in the Context of Glycogen Metabolism. Int J Mol Sci 2015; 16:25959-81. [PMID: 26528968 PMCID: PMC4661798 DOI: 10.3390/ijms161125939] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/27/2015] [Accepted: 10/16/2015] [Indexed: 01/15/2023] Open
Abstract
Glycogen metabolism has important implications for the functioning of the brain, especially the cooperation between astrocytes and neurons. According to various research data, in a glycogen deficiency (for example during hypoglycemia) glycogen supplies are used to generate lactate, which is then transported to neighboring neurons. Likewise, during periods of intense activity of the nervous system, when the energy demand exceeds supply, astrocyte glycogen is immediately converted to lactate, some of which is transported to the neurons. Thus, glycogen from astrocytes functions as a kind of protection against hypoglycemia, ensuring preservation of neuronal function. The neuroprotective effect of lactate during hypoglycemia or cerebral ischemia has been reported in literature. This review goes on to emphasize that while neurons and astrocytes differ in metabolic profile, they interact to form a common metabolic cooperation.
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Affiliation(s)
- Anna Falkowska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University, Broniewskiego 24, 71-460 Szczecin, Poland.
| | - Marta Goschorska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Przemysław Nowacki
- Department of Neurology, Pomeranian Medical University, Unii Lubelskiej 1, 71-225 Szczecin, Poland.
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
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3
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Abstract
The experience of hypoglycemia is probably the most feared and hated consequence of life with type 1 diabetes among pediatric patients and their parents. Although transient detrimental effects are clearly disturbing and may have severe results, there is surprisingly little evidence of long-term CNS damage, even after multiple hypoglycemic episodes, except in rare instances. Despite the latter evidence, we advocate that every treatment regimen be designed to prevent hypoglycemia without inducing unacceptable hyperglycemia and increasing the risk of micro- and macrovascular complications.
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Affiliation(s)
- Christopher Ryan
- Department of Psychiatry, University of Pittsburgh, Western Pennsylvania Psychiatric Institute and Clinic, Pittsburgh, PA 15213, USA
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Tkacs NC, Pan Y, Raghupathi R, Dunn-Meynell AA, Levin BE. Cortical Fluoro-Jade staining and blunted adrenomedullary response to hypoglycemia after noncoma hypoglycemia in rats. J Cereb Blood Flow Metab 2005; 25:1645-55. [PMID: 15902194 DOI: 10.1038/sj.jcbfm.9600152] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Intensive insulin therapy in patients with type 1 diabetes mellitus reduces long-term complications; however, intensive therapy is also associated with a three-fold increase in hypoglycemic episodes. The present study in conscious rats characterizes the physiologic and neuropathologic consequences of a single episode of moderate hypoglycemia. In this model, intravenous insulin is used to reduce plasma glucose to 30 to 35 mg/dL for 75 mins. This single hypoglycemic insult acutely induces hypoglycemia-associated autonomic failure (HAAF), with epinephrine responses to hypoglycemia reduced more than 36% from control. Neuropathology after this insult includes the appearance of dying cells, assessed with the marker Fluoro-jade B (FJ). After hypoglycemic insult, FJ+ cells were consistently seen in subdivisions of the medial prefrontal cortex, the orbital cortex, and the piriform cortex. There was a significant correlation between depth of hypoglycemia and number of FJ+ cells, suggesting that there is a critical threshold below which vulnerable cells begin to die. These data suggest that there is a population of cells that are vulnerable to moderate levels of hypoglycemia commonly experienced by patients with insulin-treated diabetes. These cells, which may be neurons, are primarily found in cortical regions implicated in visceral perception and autonomic control, raising the possibility that their loss contributes to clinically reported deficits in autonomic and perceptual responses to hypoglycemia.
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Affiliation(s)
- Nancy C Tkacs
- School of Nursing, University of Pennsylvania, Philadelphia, PA 19104-6096, USA.
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McCall AL. Diabetes mellitus and the central nervous system. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 51:415-53. [PMID: 12420366 DOI: 10.1016/s0074-7742(02)51012-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Anthony L McCall
- University of Virginia School of Medicine, Division of Endocrinology & Metabolism, Department of Internal Medicine, UVA Health System, Charlottesville, Virginia 22908, USA
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7
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Mooradian AD, Chehade J, Hurd R, Haas MJ. Monosaccharide-enriched diets cause hyperleptinemia without hypophagia. Nutrition 2000; 16:439-41. [PMID: 10869900 DOI: 10.1016/s0899-9007(00)00229-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To determine the effect of monosaccharide-enriched diets on plasma leptin and food consumption, body weight, food intake, and serum glucose, insulin, and leptin concentrations were measured in rats maintained on a 10-d course of 60% glucose or 60% fructose diet. The serum leptin concentration in rats fed a high-glucose diet (7.60 +/- 0.6 ng/mL) or a high-fructose diet (5.12 +/- 0.8 ng/mL) was significantly increased compared with that in control rats (2.45 +/- 0.10 ng/mL; P < 0.001). To ascertain that the observed effect was related to hyperinsulinemia, a group of rats were infused with exogenous insulin or rendered insulin resistent with a high-fat diet. When hyperinsulinemia was induced with exogenous infusion, the serum leptin was increased (5.56 +/- 0.23 ng/mL; P < 0.001). High-fat feeding was associated with increased serum leptin (12.1 +/- 1.4 ng/mL) and insulin levels. The increased serum leptin concentration was not associated with decreased food intake. We conclude that monosaccharide-enriched diets, probably through hyperinsulinemia or relative or absolute insulin resistance, cause hyperleptinemia, which does not appear to change feeding behavior.
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Affiliation(s)
- A D Mooradian
- From the Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, Saint Louis University Medical School, St. Louis MO 63104, USA
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Golding EM, Steenberg ML, Contant CF, Krishnappa I, Robertson CS, Bryan RM. Cerebrovascular reactivity to CO(2) and hypotension after mild cortical impact injury. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H1457-66. [PMID: 10516183 DOI: 10.1152/ajpheart.1999.277.4.h1457] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebrovascular reactivity to CO(2) or hypotension was studied in vivo and in vitro [pressurized arteries ( approximately 82 micrometer) and arterioles ( approximately 30 micrometer)] at 1 h after mild controlled cortical impact (CCI) injury in rats. The cortical perfusion response [assessed using laser-Doppler flowmetry (LDF)] to altered CO(2) was diminished (up to 81%) after mild CCI injury. The responses to CO(2) alterations in arteries and arterioles isolated from the injured cortex were similar to responses in vessels isolated from sham-injured animals. After mild CCI injury, the autoregulatory response to hypotension (measured using LDF) was maintained or even enhanced, depending on the method used to measure the response. Vessels isolated from the injury site showed a response to changes in pressure similar to that in vessels isolated from sham-injured rats. We conclude that mild CCI injury produces complicated alterations in cerebrovascular control. Whereas the autoregulatory response to hypotension was maintained or even enhanced, the in vivo vascular response to CO(2) was severely compromised. The altered response to CO(2) was not caused by an intrinsic vascular perturbation but rather an altered milieu after mild CCI injury.
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Affiliation(s)
- E M Golding
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030, USA.
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MacLeod KM, Gold AE, Ebmeier KP, Hepburn DA, Deary IJ, Goodwin GM, Frier BM. The effects of acute hypoglycemia on relative cerebral blood flow distribution in patients with type I (insulin-dependent) diabetes and impaired hypoglycemia awareness. Metabolism 1996; 45:974-80. [PMID: 8769355 DOI: 10.1016/s0026-0495(96)90266-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To examine the hypothesis that in diabetic patients with impaired hypoglycemia awareness the relative regional distribution of cerebral blood flow (rCBF) would be abnormal in a specific area, namely the frontal lobes, rCBF was examined in 20 type I diabetic patients, of whom 10 had a normal awareness of hypoglycemia and 10 had a history of impaired hypoglycemia awareness. rCBF was determined sequentially using single photon emission computed tomography (SPECT) during (1) normoglycemia (arterialized blood glucose 4.5 mmol. L-1) and (2) hypoglycemia (blood glucose 2.5 mmol.L-1) induced by a hyperinsulinemic glucose clamp technique. Distribution of the isotope, 99mTc-Exametazime, was detected using a single-slice multi-detector head scanner. A split-dose technique was used, with 250 MBq being injected during steady-state normoglycemia and 250 MBq during subsequent hypoglycemia. rCBF was estimated in 30 regions of interest, derived from a standard neuroanatomical atlas on two parallel slices at 40 and 60 mm above the orbitomeatal line (OML). No between-group differences in the pattern of overall rCBF or changes in regional tracer uptake were demonstrated. In comparison to the rCBF during normoglycemia, both patient groups exhibited significant changes in the pattern of rCBF during hypoglycemia, with increments of rCBF to both superior frontal cortices and the right thalamus and reduced rCBF to the right posterior cingulate cortex and the right putamen. This pattern of relative redistribution of rCBF during hypoglycemia was preserved in patients who had impaired hypoglycemia awareness.
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Affiliation(s)
- K M MacLeod
- Department of Diabetes, Royal Infirmary, Edinburgh, Scotland
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Abstract
Studies of CBF have provided some insight into cerebrovascular physiology and pharmacology. However, the precise relation between CBF and cerebral damage remains elusive, and there is no definition of a threshold CBF below which ischaemic brain damage always occurs. Measurement of CBF thus does not currently provide a secure guide in the clinical management of sick infants. Further work, particularly using techniques like magnetic resonance imaging and NIRS, which provide data in addition to CBF measurements, may yet disclose strategies which manipulate CBF to reduce cerebral ischaemia. While cerebral injury remains a substantial problem in neonatal intensive care, such research is urgently needed.
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Affiliation(s)
- O Pryds
- Department of Neonatology, Rigshospitalet, Copenhagen
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Abstract
Neonatal cerebral oxygen delivery was estimated in 93 preterm infants (gestational age < 34 weeks) who survived the neonatal period. Of these, 26 had developed neurological handicap at follow-up 1.7-4.6 years later. Neonatal cerebral oxygen delivery was dependent on gestational age, and was also related to the degree of intra-uterine growth retardation, carbon dioxide tension, and blood glucose concentration. Lower oxygen delivery was observed in infants who developed germinal layer haemorrhage or periventricular leucomalacia compared with infants with normal brains. However, as no information on cerebral metabolic demand or oxygen extraction is available, it is unclear whether decreased oxygen delivery is a contributing factor to brain damage or whether it is a marker of existing injury.
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MESH Headings
- Birth Weight
- Blood Pressure/physiology
- Brain/blood supply
- Brain Damage, Chronic/blood
- Brain Damage, Chronic/etiology
- Carbon Dioxide/blood
- Cerebral Hemorrhage/blood
- Cerebral Hemorrhage/etiology
- Gestational Age
- Humans
- Hypoxia, Brain/blood
- Hypoxia, Brain/etiology
- Infant, Newborn
- Infant, Premature, Diseases/blood
- Infant, Premature, Diseases/etiology
- Leukomalacia, Periventricular/blood
- Leukomalacia, Periventricular/etiology
- Neurologic Examination
- Oxygen/blood
- Positive-Pressure Respiration
- Regional Blood Flow/physiology
- Risk Factors
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Affiliation(s)
- O Pryds
- Department of Neonatology, Rigshospitalet, Copenhagen, Denmark
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12
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Pelligrino DA, Segil LJ, Albrecht RF. Brain glucose utilization and transport and cortical function in chronic vs. acute hypoglycemia. THE AMERICAN JOURNAL OF PHYSIOLOGY 1990; 259:E729-35. [PMID: 2122741 DOI: 10.1152/ajpendo.1990.259.5.e729] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We compared regional brain capillary permeability-surface area products for glucose transfer (PSin), cerebral glucose utilization (rCMRGlc) rates, and brain tissue glucose levels (GlCbr) in N2O-sedated, paralyzed, and artificially ventilated rats during normoglycemia (NG), insulin-induced acute hypoglycemia (AH), or chronic hypoglycemia (CH) [hypoglycemic plasma glucose (Glcp) = 2.2-2.3 mumol/ml]. In addition, a comparative assessment of brain function in AH vs. CH was performed employing somatosensory-evoked response (SSER) technology. A double-label (3H and 14C) 2-deoxy-D-glucose method was used for the simultaneous assessment of PSin and rCMRGlc. Compared with normoglycemic controls, AH resulted in significant 40-50% reductions in rCMRGlc in 10 of 11 regions analyzed (cerebellum unchanged). In CH vs. AH, significantly higher values for rCMRGlc, Glcbr/Glcp ratios, and PSin were seen in 8, 8, and 5 regions, respectively. No differences in rCMRGlc were observed when comparing CH vs. NG groups. Furthermore, CH rats were able to sustain normal SSER at levels of hypoglycemia (1.5 mumol/ml) that, when imposed acutely, resulted in attenuated SSER. Thus CH is associated with an enhanced blood-brain glucose transport capacity in many (but not all) brain regions. This in turn increases rCMRGlc and improves the general cerebral function compared with that seen during AH.
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Affiliation(s)
- D A Pelligrino
- Department of Anesthesiology, Michael Reese Hospital and Medical Center, Chicago, Illinois 60616
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